This invention relates generally to clamps of the type used to temporarily clamp two articles together, for example, for gluing, or to hold a work-piece for welding or other operation, and more particularly, to a quick-action clamp capable of clamping work-pieces having a wide range of sizes.
Clamps of various configurations are old and well known, among them traditional parallel wood clamps, long used by woodworkers, and available in several capacities to accommodate a variety of clamping situations. Their effectiveness is limited, however, in that many different clamps are required to accommodate a range of work-piece sizes. For example, six traditional wood clamps ranging in size from four inches to eighteen inches are required to clamp work-pieces varying in thicknesses from zero to eighteen inches.
A relatively recent entry into the prior art is the quick-action "Quick Grip" clamp marketed by Peterson Manufacturing Co., Inc. This clamp has a movable jaw which is rapidly movable over both short and long distances to clamp against a work-piece, and is operable with one hand. The movable jaw is connected to one end of a movable slide bar and a stationary jaw is supported on the slide bar by a support structure including a trigger handle grip which releasably engages the slide bar and advances the movable jaw toward the fixed jaw. Four of these clamps ranging in opening size from six inches to twenty-four inches are required to clamp work-pieces varying in thickness from zero to twenty-four inches. It also has the disadvantage that once the jaws are initially clamped against a work-piece, the lever mechanism is so constructed that the hand cannot apply sufficient force on the trigger handle to advance the movable jaw by another increment, with the consequence that the clamp lacks the power to adequately clamp two articles together.
Thus, there is a need for a universal clamp, for use by woodworkers and others, capable of clamping a work-piece of any size within a relatively large range, say, between essentially zero and twenty-four inches, while having a closed length significantly shorter than the maximum opening of the clamp, and is capable of providing large clamping forces.